Swimming Pool Blog

10 Tips: Measuring for a Safety Pool Cover

Measuring for a Pool Safety Cover
by Rob Cox August 29, 2017

Measuring for a Custom Safety Pool Cover

Go from this... to this! Measuring a pool for a safety cover, doing A-B measurements, as they are called, should take you 30-60 minutes, depending on the size and complexity of the pool shape.

If you are planning to install your own safety cover - you will also be responsible for sending in accurate measurements of your pool to a safety cover dealer (like Poolcenter!). :-)

When we prepped for our days out in the field, we would make sure that we had the following loaded onto the truck:

  • 100 ft tape measure, reel type
  • Two narrow stakes, 12-24 in. long
  • Roll of Duct Tape and a Sharpie Pen
  • Measuring Form, Clip Board
  • Helper that can write legibly

Tips on Measuring a Pool for a Custom Safety Cover

duct tape, instead of chalk

1. Most instructions for measuring the pool will say to use chalk, but I prefer to use small strips of duct tape. Chalk can take weeks or months before the rain washes it away. But you do need dry coping, it won't stick well to wet.

Unroll about 12" of duct tape, then tear again twice lengthwise, into 3 long 1/2 in. strips. As you walk around the pool,  tear off 2" long strips, and stick them firmly just over the inside edge of the pool coping. Only stick the back half of the tape strip to the pool coping, leave a front tab unstuck - it makes it easier to remove the tape after measuring.

2. Write every fifth (5th) number on the back half of the duct tape pieces with a sharpie pen, starting with number 1, then 5, 10, 15... and ending with your final, last point, adjacent to your number 1 point. This step is important, for good reference and help making your drawing, and for best communication with your helper writing down the numbers.

3. For your A-B stakes, you can use a piece of 3/8 in. steel rebar or wooden dowel, or garden stakes. A very long (15-18 in.) Phillips screwdriver can be used. It's best to have a narrow stake, so that you can slip the metal end of the measuring tape over the end of the stake, and it will swivel as you move the tape around the pool. You could also use larger wooden stakes pounded into the ground, with a nail on the top. A safety cover hex key also makes a very nice stake for AB measurements.

4. The location of your A-B stakes is an important choice. Choose the side opposite any water features, boulders or obstructions, and the side that makes it easiest to move the measuring tape around the pool, without having to wrap around any poles or rocks or navigate deck level changes. Choose a location with some soil areas, for easiest placement of your stakes. In cases with no soil, use a tall flathead screwdriver, lightly pounded in between concrete slabs or deck drains. If that is not available, you can make duct tape "X" marks on the concrete, and have the helper hold the tape end on center of X for each measurement. A and B stakes should be separated by at least 1/2 the length of the pool, or about 20 ft apart for most pools, and 3-5 feet from the pool edge. A straight line drawn between points A and B can never intersect the pool.

5. Whichever type of stake you use for your A and B points, make sure they are placed firmly and deeply into the ground, so they won't lean or move when you are pulling the tape from across the pool. And, don't overdo it either and pound stakes too deeply, if there is a possibility of pool plumbing pipes within a foot of the surface. If possible, leave the stakes in place (or mark the spots), until after your measurements have been approved, just in case there is a need to double check some measures. 

6. On curves and irregular points, take measurements to points at the beginning, apex and end of the curve, or every 1-2 feet. On straight runs of pool wall, you can set points 3-4 feet apart. Measure 90 degree corners, at the corner. Non-removable obstructions within 15" of the pool edge should also be marked. These may include rails, spillways, fill spouts, slide legs, rocks or boulders, deck level changes or anything that is not removable for winter and is within 1-2 feet of the pool edge.

7. Always round up, or always round down - to the nearest inch, as you shout out your measurement to your helper. Have them shout it back to you as they write it down, to improve accuracy. Every fifth (5th) measurement, call an audible on the point number (that you wrote on the duct tape), such as "...and for point number 5, we have...."

8. If you end up with your 'A' measurements having more points than you have in the 'B' column, or vice-versa, that means you either skipped a point, or measured a point twice. Work backwards and remeasure every fifth point, until you find the area where the mistake occurred, then find the point that was missed, or duplicated. 

9. Most measurement mistakes are caught by the manufacturer, because they produce mathematical inconsistencies or make the shape of the pool unlikely or impossible. Measure carefully nonetheless, and fill out all of the other sections of the measurement form thoughtfully, because you don't want to have to do it twice! Email pictures for raised walls, water features, planters or cut-outs, or areas of less than 3 feet of decking.

10. Drawing the picture of the pool on graph paper may test your art skills, but it need not be perfect. Use a pencil and draw lightly, as you may want to erase and correct some of the curves. When the picture is a close representation of the pool shape, carefully make small marks around the edge lightly in pencil, to represent each point, and also draw in the location of your A and B points. Number every fifth (5th) point on your drawing, and show the location of any obstructions, walls, steps or other obstructions.

If you are replacing an existing cover, you can also measure to each existing anchor, but in most cases, not every safety cover anchor will line up with every strap, many may need to be redrilled. When the picture and points are drawn-in to the best of your ability, use a pen to darken the drawing and numbers if needed.


I wish we had done a video on measuring for custom safety pool covers. Here's a great video that I came across produced by pools.com. Give it a watch for the process of A-B measurements on a custom pool.


Get your measurements in early, safety pool covers can take 3 weeks to produce, after your measurements have been received. Replacement covers are slightly faster, if you have your original order number or invoice number from the manufacturer.

For any assistance with measuring, ordering or installing a safety cover, send me an email, or fill out a question in our Pool Forum, or our Ask the Expert page, both which I moderate, or you can always call our call center and ask to speak to our safety cover specialists, who can answer any questions you have over the phone. 877-766-5287


- Rob